Lubrication system



July 2, 1946. 'D, R RANKIN 2,403,397v

' LUBRICATION SYSTEM Filed Oct. 19, 1942 2 Sheets-Sheet l July 2, 1946. R, R NK 4 2,403,397

LUZBRICATIOIZI SYSTEM Filed Oct. 19, 1942 i .2 Sheets-Sheet 2 Patented duty 2,. i dfi curred srmras PATENT osric 2.403.391 LUBRICATION SYSTEM Dan R. Rankin, Los Angeles, Calif., assignor to Food Machinery Corporation, a corporation of Delaware Application October 19,-1942, Serial No. 462,485

7 Claims. 1

This invention relates to the lubrication art and particularly to pressure lubrication systems.

It is an object of this invention to provide a novel pressure. lubricating system suitable for use on the bogie wheels of military tanks.

Such tanks operate in the presence of large amounts of abrasives, that is, sand and dust, and if amphibious must operate also frequently in the water, and it is essential that no abrasive orwater be admitted into the bearings of these wheels.

It is accordingly another object of my invention to provide a pressure lubrication system suitable for use in bogie wheels which will completely exclude all foreign substances from admission into the bearing structure of the wheel.

While attempts have been made to accomplish the foregoing object by applying pressure to a lubricant inside a wheel, the pressure thus applied has varied substantially with fluctuations in the atmospheric temperature. Unfortunately, the higher temperatures not only increase the pressure placed on the lubricant but increase the fluidity of the lubricant so as to re's'ultin undue loss of the latter in very hot weather. I

Then, when relatively low temperatures are encountered or a rapid drop in temperature takes place as when plunging into Water after travelling over desert landfa subatmospheric pressure can develop within the wheel which will suck dirt or mud into the wheel bearings. If this occurs the bogie wheel bearings wear out much earlier than they otherwise would, thus depriving our armed forces prematurely of the further use of those tanks which are equipped with these bearings.

It is a further object of my inventionto provide a pressure lubricating system suitable for use in bogie wheels in which pressure applied to the lubricant is substantially unaffected by fluctuations in surrounding temperatures.

The manner of accomplishing the foregoing objects as well as other will be made manifest in the following description taken in connection with the accompanying drawmgs in which Fig. 1 is an elevational view of a bogie wheel with the central portion thereof in section to illus- ;rate the structure and mode of operation of a Jreferred embodiment of the invention with vhich said wheel is equipped. Fig. 2 is a longitudinal sectional view of the ressure cylinder of the invention at an internediate stage of it assembly.

Fig. 3 is a view similar to Fig. 2 showing the lext step in the assembly of said cylinder.

objects and advantages San Jose, Qaliii,

the final step in the assembly cf said cyl inder. Eig. 5 is a longitudinal view illustrating a modi- 'fied form of theinvention. 5 Referring specifically to the drawings, the bogie wheel I0 is shown therein as including an axle M, an outer wheel structure l2, and a pair of bearings |3 by which the outer structure I2 is mounted on the axle Also disposed betweenthe axle ii and outer structure I 2 are lubricant retaining seals I4.

Axle comprises'a piece of'steel' shaftlng 20 provided with annular bearing shoulders 2| and having a bore 22 formed axially therein throughout its length. Opposite ends of the bore 22 have counterbores 23 and 26 provided with tapered threads 25 and 26 respectively. Formed radially in the piece of shafting 20, midway between its ends and communicating between the bore 22 and the exterior surface of the shafting, is a hole 21.

Th'e'outer wheel structure l2 has a hub portion 30 having af'central bore 3| at opposite ends of which'are shoulders32 which lie in planes spaced apart a slightly lessdistance than the bearing I shoulders 2| on the shaft 20. The bearings |3 fit inwardly snugly against the shoulders 2| and are held in place by sleeves 33 which are pressed .over the opposite end portions of the shaft 20 against the inner races of the bearings l3. The

sleeves 33 have non-corrosive bushingsy36 disposed adjacent to the bearings I3. Threaded counterbores 31 are provided infopposite ends of the bore 3| and the seals M are 5 screwed into these counterbores so that lubricated sealing rings 38 thereof come into snug sealing engagement with the outer surface of the bushings 36. One of the seals I4 is utilized to bind the outer race of the adjacent bearing l3 against 40 the, adjacent shoulder 32 of the wheel hub 30; This bearing thus takes up axial thrust shocks to which the wheel I ll is subjected.

The space between the bearings I3, Within the borejl and outside the axle H, constitutes a lubricant chamber 39.

v Mounted in the bore 22 of the axle H is a lubricant pressure element 50. This element has a base plug 5| which screws into the threads 26. This plu has a central hexagonal opening 52 and a central threaded opening 53 which communicates with a hole 54 formed transversely therein, opposite ends of which open into the counterbore 24. The inner end of the plug 5| is turned down to form a cylinder head 55 which extends into and closes one end of a tubular Fig. 4 is a view similar to Flg. 3 and illustrates normally much of the spring.

thus been forced into the chamber 6|, a pm 1|.

brazed or tend cylinder 56, the latter being soldered,

to completely close the.

welded to the plug 5| of the cylinder 56.

When the element 5|) is installed as shown in Fig. l, the cylinder 56 thereof extends through the bore 22 as far as the counterbore 23 so as to give this cylinder the maximum practicable length. Screwed into thethreaded hole 53 of the plug 5| is a pressure release valve to release lubricant from inside the bogle wheel when pressure of this exceeds a given safety factor. It is here to be noted that the outside diameter of the cylinder 56 is less than that of the bore 22 so that free communication is mamtained through the annular space and with the hole 56 and valve 56 in the plug Compressed within the cylinder chamber 6| is a coiled expansion spring 65. The spring 65 is longer than the cylinder chamber 6| and is adapted to be compressed therein by application of a. plunger 16 tov the outer end After the spring and plunger have is fixed in the mouth of this, chamber to prevent the plunger and spring from escaping. I

Theplunger 16 may be of any suitable construction but preferably includes a pair of flexible cup washers I2 which are trapped between flanged guide blocks 13 and a washer H, all of which are held in assembled relation by a screw 15. g

The counterbore 23 zls closed by a plug 8|! screwed into the threads 25, this plug having a hexagonal central opening BI and a threaded hole 82 in which is screwed a Zerk check valve fitting 83.

Operation When the bogie wheel I6 is assembled the chamber 36 and hole 21 are filled with grease and the plug 86 is screwed into place before the element 50 is installed. Before explaining how this is done it will be necessary of assembly of this element.

Prior to inserting the plunger I6 into the cylto describe the mode 59 adapted 7 6|) between the hole 21, the chamber 6| within the cylinder 56,

' by suitable clamps inder chamber 6|,a quantity of grease 96 is placed in this chamber back of the ing been done, the

plunger. This havspring 65 is compressed in the chamber 6|, the plunger 10 inserted and the pin 1| secured in place as shown in Fig. 2.

The unit may then remain as thus shown until the time comes to install it in the bogie wheel It. At that time the unit 50 may be cooked by the use of a rod 9| as shown in Fig. 3. This rod is extended into the chamber 6| past the stop pin 1| into engagement with the plunger 10 so as to force this plunger toward the cylinder head at the closed end of the cylinder until the to trap the spring and plunger spring is completely collapsed with itsadjacentcoils in contact with each other. The quantity of grease disposed in the chamber 6| is sufficient so that before'the spring 65' has been thus collapsed all the space betweenthe plunger 10 and the cylinder head 55 is filled with this grease so that a'quantity 92 of this grease overflows past the cup washers 13 of the plunger 10.

When the spring 65 has thus been entirely collapsed so as to comprise a stop preventing further movement of the plunger Ill towards the cylinder head '55, the pressure is relaxed on the rod 9| permitting the spring 65 to expand and return the plunger 10 back to the position in which it engages the stop pin 1| as tention being given wheel as the grease will be supplied under subbe substantially the same.

.intervals are fixed so charged with grease before the plunger 16 comes- 60 and applying a rod 4. Except for thespace occupied by the grease 90, the space between 55in the cylinder evacuatedof air. vacuum.

The element 50 is now ready to be inserted chamber 6| is now completely into the axle bore 22 and the plug 5| screwed snugly-into the threads 56 as shown in Fig. 1. Before being thus inserted, a certain amount of grease is placed in the bore 22 so that when the plug 5| is in place all the space in the. bore 22 surrounding the element 56 is filled with grease.

A grease gun is now applied to the Zerk fitting 83 and grease is pumped through this fitting into the counterbore 23 from which it passes into the cylinder chamber 6| .and compresses'the spring When thus assembled and charged with grease,

b'ogie wheel I6 is assembled on a military tank on the frame of the tank bein applied to the sleeved ends of the axle i. During the operation of the tankand the bogie wheel NJ, the latter will be lubricated by grease replenished by the operation of the spring 65 until the plunger HI again comes to rest against the stop pin 1|. Throughout this period there is no'need for atto the lubrication of this stantially constant pressure to the bearings l3, this pressure being always in excess of the at mospheric pressure outside of the wheels H. Thus a slight leakage of grease between the packing material 38 and the bushings 36 will take place but only sufllcient to washfrom the space between these elements any slight amount of abrasive which might be thrown against this portion of the wheel.

'Furthermore it is to be noted that extremes of temperature to which the bogie wheel might be subjected during this period of its operation will in no wise alter the action of the spring 65 and the amount of pressure which it places on the lubricant within the whee1 will at all times This is because the spring 65 is completely sealed from the outside pressure and is surrounded by a vacuum.

The lubricant in the chamber 6| is of course replenished at intervals by recharging the wheel through fitting 83 in accordance followed automotive lubricating practice. These that each wheel I0 is rein contact with the stop pin 1|. Thus grease is always fed to the bearings l3 under pressure from the spring 65.

It is to be noted that if grease should leak around. the plunger I6 so that the element 50 will not receive its maximum plunger Ill can be reset charge of grease, the by removing the plug to plunger 10 as shown inFig.3.

shown-in Fig. 15 of In Fig. 5 I have illustrated an alternative form of the invention in which a core 95 is provided in the closed end of a cylinder 96 which may be substituted for the cylinder 56 of the element .56.

The function of the core 95 is to occupy most the space within the spring 65 when this is the plunger 10 and the head That is, it is occupied by a with universally compressed as shown in Fig. 3, thereby obviating the necessity of a relatively largequantity of grease 90 in the chamber 6| between the plunger 10 and the closed end of the cylinder.

What I claim is:

1. In a lubrication system for supplying lubri cant to a lubricant chamber, the combination of: means forming a cylinder having an air-tight closed end, the open end oi said cylinder being adapted to communicatejwith' said chamber; a cup plunger disposed in said cylinder and adapted when lubricated to make an airtight fit therewith; and an expansion spring in said cylinder between the closed end thereof and said plunger, said spring having sufllcient expansive strength when compressed to expand and force said plunger toward the open end of said cylinder against the pressureof the atmcxsphere.

2. In a lubrication system for supplying lubricant to a lubricant chamber, the combination of: means forming a cylinder having an air-tight closed end, the open end of said cylinder being adapted to communicate with said chamber; a

cup plunger disposed in said cylinder and adapted when lubricated to make an airtight fit therewith; an expansion spring in said cylinder between the closed end thereof and said plunger,

said spring having suflicient expansive strength when compressed to expand and force said plunger toward the open end 01' said cylinder against the pressure 01' the atmosphere and stop means at the open end of said cylinder to retain said plunger therein against the expansive force of said spring.

3. In a lubrication system for supplying -1ubri.. cant to a lubricant chamber, the combination of: means forming a cylinder having an air-tight closed end, the open end 01' said cylinder being adapted to communicate with said chamber; a cup plunger disposed in said cylinder and adaptedwhen lubricated to make an airtight fit therewith: an expansion spring in said cylinder between the closed end thereof and said plunger, said spring having sumcient expansive strength when compressed to expand and force said plunger toward the open endof said cylinder against the pressure of the atmosphere; and a core oi incompressible material disposed within said cylinder to substantially fill the space located within the coils oi. said spring and between said plunger and the closed end 0! said cylinder when said spring is fully compressed.

4. In a lubrication system for supplying lubricant to a lubricant chamber, the combination 01': means forming a cylinder having an air-tight a to substantially said spring having suflicient expansive strength whencompressed to expand and force said plunger toward the open end of said cylinder against the pressure of the atmosphere; and a quantityof grease disposed within said cylinder fill the space located within the coils of said spring and between said plunger and the closed end of said cylinder when said spring is fully compressed- 5. In combination: an axle adapted to rotatably support a wheel, said axle having an axial bore extending therethrough to form a lubricant chamber, and passage means to conduct lub'ricant from said chamber to a wheel carried by said axle; closures provided for opposite ends of said bore; a tube provided on one of said closures and fitting loosely in said chamber; a plunger in said tube; a spring in said tube between said plunger and the closure to which said tube is attached; a check valve; and an escape valve, one of said valves being provided upon each of said closures, there being passage means provided placing each of said valves in communication 310th the space outside said tube and within said 6. In combination: an axle adapted to rotatably support a wheel, there being a bore extending axially through said axle to form a lubricant chamber, there being passage means provided in said axle to conduct lubricant from said chamber to a wheel carried bysaid axle, the opposite ends of said bore being internally threaded; screw plugs adapted to be received by said threaded bore ends; a tube. provided on one of said plugs and adapted to be extended into said chamber when said plug is inserted in one end of said bore; a plunger in said tube; a spring in said. tube between said plunger and the plug on which said tube is mounted; an intake check valve; and a pressure relief valve, one of said valves being mounted in each of said cups to communicate with space within said bore about said tube.

7. A combination as in claim 5 in which said closure on which said tube is mounted completely closes the end oi'said tube which is secured thereto thereby forming an air tight space between said closure and the plunger in said tube.

DAN R. RANKIN. 

